The present application relates to a hinge structure particularly usable for spectacle frames.
Numerous kinds of hinges are currently known; the simplest are constituted by cams which protrude at the end of a rod and are associated at tabs which protrude at the end of the frame by means of a locking screw.
Said known hinges, however, require the user to fold them approximately parallel to the lens in the frame in case of non-use for storage, and furthermore do not ensure a good grip of the rod at the temples.
The repositioning of the frame is thus inconvenient, and said frame can slip off due to a sudden movement.
As a partial solution to these disadvantages, hinges are known which comprise rods which have, at one end, an axial cavity which acts as seat for a spring and a ball which interacts with a cam defined at the end of the front portion of the frame.
Such known hinge types therefore allow an extra opening beyond the condition of approximately ninety degrees with respect to the plane of arrangement of the front portion, so as to allow them to adhere optimally at the temples of the users in order to prevent the spectacles from slipping off.
Other known hinges furthermore provide the automatic repositioning of the rod proximate to the front portion once a small rotation toward said front portion has been imparted thereto starting from the condition of normal use.
All these known types of hinge, however, essentially have the disadvantage of being expensive, both because they are constituted by a large number of components which require special and accurate assembly and because it is necessary to use materials which are not subjected to considerable wear due to the extremely large number of operations for opening and closing the rods with respect to the front portion performed every day by the user.
Another disadvantage resides in that said known types of hinge also have not optimum dimensions and consequent aesthetic solutions, due to the need to accommodate all the components in order to achieve the extra opening or the automatic closure of the rod.